Assistant Prof. Phil King
University of St Andrews
时间：6月19号 周五 上午10点
地点：唐仲英楼B-501
Methods to generate spin-polarized electronic states in non-magnetic solids are strongly desired to enable all-electrical manipulation of electron spins for new quantum devices. This is generally accepted to require breaking global structural inversion symmetry. In contrast, I will report our observation from spin- and angle-resolved photoemission spectroscopy of spin-polarized bulk states in the centrosymmetric transition-metal dichalcogenide 2H-WSe2 [1]. I will show how this occurs due to local inversion symmetry breaking within constituent sub-units of the bulk crystal where the electronic states are localized, allowing enormous spin splittings of up to ~0.5 eV to develop with a spin texture that is strongly modulated in both real and momentum space. Through this, our study provides direct experimental evidence for a putative locking of the spin with the layer and valley pseudospins in transition-metal dichalcogenides, of key importance for using these compounds in proposed valleytronic devices.